1. Field of the Invention
The present invention relates to a liquid crystal display used as a display section of an electronic apparatus and a method of manufacturing the same, and more particularly to an MVA type liquid crystal display having high viewing angle characteristics and a method of manufacturing the same.
2. Description of the Related Art
Recently, liquid crystal displays are widely used in various applications taking advantage of their features such as low profiles and light weights, low-voltage drivability and low power consumption. Further, some liquid crystal displays are available with display characteristics comparable to those of CRTs and are therefore being put in use as monitors and television receivers for which CRTs have been dominantly used.
Among liquid crystal displays that are currently in practical use, MVA (Multi-domain Vertical Alignment) displays are one of types which exhibit high display characteristics comparable to those of CRTs. In an MVA type liquid crystal display (herein after referred to as “MVA-LCD”), liquid crystal molecules are aligned substantially perpendicularly to a substrate surface when no voltage is applied. When a voltage is applied, the liquid crystal molecules are aligned in a predetermined direction that is regulated by alignment regulating structures formed on a substrate surface. Alignment regulating structures include protrusions, recesses, and blanks (slits) in an electrode.
FIG. 37 shows a configuration of three pixels of a common MVA-LCD. As shown in FIG. 37, linear protrusions 1102 and 1104 in a zigzag configuration constituted by dielectric bodies are formed on a pair of substrates provided opposite to each other, respectively. The linear protrusions 1102 formed on one of the substrates and the linear protrusions 1104 formed on the other substrate are disposed alternately. Thus, liquid crystal molecules are tilted in a different direction in each of regions A, B, C and D. Liquid crystal molecules in one pixel are tilted in four directions in the regions A, B, C and D, respectively, each of the directions being at a differential angle of about 90°. Thus, four domains of alignment are obtained.
Patent Document 1: JP-A-2000-356773
Patent Document 2: JP-A-2002-357830
Patent Document 3: Japanese Patent No. 2947350
Patent Document 4: JP-A-H11-242225
FIG. 38A is a graph showing transmittance-voltage characteristics (T-V characteristics) of the MVA-LCD shown in FIG. 37. The abscissa axis represents voltages (V) applied to the liquid crystal, and the ordinate axis represents transmittances (%) of light. The line X1 in the graph indicates T-V characteristics in a direction perpendicular to the display screen (hereinafter referred to as “square direction”), and the line X2 indicates T-V characteristics in an upward direction at a polar angle of 60° to the display screen (hereinafter referred to as “oblique direction”). A polar angle is an angle to a line perpendicular to the display screen. The display mode of the MVA-LCD is the normally black mode in which a voltage (absolute value) applied to the liquid crystal is decreased to display black and increased to display white. As shown in FIG. 38A, when voltages (in the range from about 2.2 to 2.9 V) in the neighborhood of a region where a threshold voltage is exceeded are applied, transmittances in the oblique direction are higher than those in the square direction.
FIG. 38B is an enlarged view of the neighborhood of the threshold voltage in the graph shown in FIG. 38A. As shown in FIG. 38B, for example, when a voltage (about 2.3 V) which provides a transmittance of 0.2% in the square direction is applied, transmittance in the oblique direction increases to about 2.5% as indicated by the arrow in the figure. In particular, when a voltage slightly in the excess of the threshold voltage is applied, since the value of the resultant transmittance itself is small, transmittance in the oblique direction increases significantly relative to transmittance in the square direction. This results in a problem in that an image displayed in halftones appears whitish in the oblique direction because of degradation of gradation/viewing angle characteristics. It is desired to mitigate this phenomenon because it can reduce display quality of an MVA-LCD.